Ninjitsu gets fast strikes. The silent strikes thing is just gravy (if you’ve also got light step, you can ghost around pretty well in the dark, though, killing zombies 3 steps from other zombies without them noticing, which can be nice). The real reason ninjitsu is stupid awesome and more OP than Krav maga?
Double damage with edged weapons.
Seriously, criting for 200+ damage with a katana, or quick striking for 40-50… yeah, squish. I can stand in open and face a horde of anything but spitters and shockers and kill them as fast as the come. Even hulks, usually (“usually” meaning “usually killing them without taking a hit”). Without bloody moving. In the open. It’s crazy.
Dielectric CBM, a gas mask, a halfway decent edged weapon (machete is sufficient), and the only zombie that gets your attention is the spitter. Nothing else is worth breaking stride for, much less being worried about.
I play on 20X monster spawn, and once the spitters are dead, enormous clumps of zombies are annoying for the tedium of butchering, nothing more. No fear, not even any equipment damage. I’m thinking about restarting without ninjutsu, just because it’s so brokenly overpowered.